The instant invention relates generally to precluding fluid wicking within an interior of a cable and, in particular, to precluding fluid wicking within an interior of a cable connected at one end to a sensor strategically deployed on assets including machinery to be monitored and operatively coupled at an opposing end to a processing unit.
A wide variety of applications in the industry of monitoring plant assets including machinery require an internal mounting arrangement of at least one transducer or sensor. For example, a mounting bracket may be used to strategically mount the transducer within a machine case and route a cable associated with the transducer out of the machine case. The routing of the cable through the machine case is usually through an adapter which includes some type of rubber grommet. The rubber grommet functions as, inter alia, a means for preventing fluid leakage through the case via an outer surface of the cable.
A junction box is typically mounted on or near the exterior of the machine case and encloses the electrical connections between the transducer cable and an extension cable that is used to route the output of the transducer to a processing unit.
As noted, the rubber grommet adequately prevents fluid from exiting through the machine case via the outer surface of the cable.
However, a long felt problem in the industry still exists in that the fluid permeates through cuts and cracks in an outer jacket of the cable and is wicked up by the interior and particularly the underlying braiding of the cable and is thus allowed to flow into the junction box and/or onto a plant floor. This not only causes a safety hazard, but an environmental hazard as well. Consequently, the junction box must be periodically drained of fluid and/or the plant floor cleaned.
Furthermore, fluid may penetrate to the interior of the cable by way of a transition area between the transducer and one end of the cable. Moreover, the transducer itself may become damaged and allow fluid ingression to be wicked up by the braiding of the cable such that fluid is drawn from within the interior of the machine case to an outside environment.
A need therefore exists for providing a cable which precludes fluid wicking within the interior of the cable such that the fluid is not drawn from within an interior of an asset including machinery being monitored to an outside environment. In addition, there is a need for a cable which precludes fluid wicking while remaining flexible so that it can be easily routed through machinery and conduit. Furthermore, there is a need for a cable which precludes fluid wicking while retaining its original ability to be readily electrically connectable to a transducer or sensor on at least one end.
The following prior art reflects the state of the art of which applicant is aware and is included herewith to discharge applicant""s acknowledged duty to disclose relevant prior art. It is stipulated, however, that none of these references teach singly nor render obvious when considered in any conceivable combination the nexus of the instant invention as disclosed in greater detail hereinafter and as particularly claimed.
The instant invention is distinguished over the known prior art in a multiplicity of ways. For one thing, the instant invention provides a communication cable which includes multiple degrees of control of fluid wicking propensity within an interior of the cable such that fluid is prevented from being drawn from within an interior of an asset such as a machine being monitored to an outside environment. In addition, the instant invention provides a communication cable for precluding fluid wicking which substantially retains its original flexibility after being impregnated with a sealing composition thereby allowing the communication cable of the instant invention to make sharp angle bends and be easily routed through machinery and conduit. Furthermore, the instant invention provides a communication cable which is impregnated with a sealing composition such that it retains its original ability to be readily electrically connectable to a transducer or sensor on at least one end.
In one embodiment of the instant invention, the communication cable is in a form of a triaxial cable. The triaxial cable includes a central strata, a penultimate strata and an ultimate strata concentrically disposed. The central strata includes a central signal transmission medium separated from the penultimate strata by a central insulator or dielectric. The penultimate strata includes a braided conductor circumscribing the dielectric and an inner jacket surrounding the braided conductor thereby forming a coaxial assembly. The ultimate strata includes a braided sheath surrounding the inner jacket and an outer jacket circumscribing the braided sheath thereby forming the triaxial cable.
The penultimate strata further includes at least one axially and radially extending zone of sealing composition or sealant which is disposed within the braided conductor and bonded to an etched exterior surface of the central dielectric. The sealant also bonds to an interior surface of the inner jacket. The ultimate strata includes axially and radially extending zone of sealing composition disposed within the braided sheath and bonded to an etched exterior surface of the inner jacket.
In one embodiment, the communication cable may be manufactured in the form of the triaxial cable which is multiple meters in length. The manufacturing process may include the step of providing the central signal transmission medium or a central conductor which longitudinally extends from a first end to a second end and covering or extruding the dielectric over the central conductor. Next, the exterior surface of the dielectric is etched, by preferable running it through a chemical liquid etching bath.
The next step is to draw or wrap the braided conductor over the etched exterior surface of the dielectric wherein the braided conductor is formed from a plurality of braided wire strands including interstices defined by spaces interposed between the wire strands forming the braided conductor.
The next step is to form a plurality of zones of sealing composition intermittently disposed along the axial length of the braided conductor. The zones are formed by intermittently extruding sealing composition through a die and under pressure for forcing the uncured sealing composition through the braided wire strands and into contact with the exterior surface of the dielectric wherein the sealing composition bonds therewith for filling in areas of tangency between the dielectric and the braided conductor at spaced apart intervals. In addition, the intermittently extruded sealing composition covers an exterior of the braided conductor and fills in the interstices defined by the spaces interposed between the wire strands of the braided conductor at spaced apart intervals. Thus, the communication cable is preferably formed to include a plurality of axial lengths of braided conductor which are substantially void of sealing composition and a plurality axial lengths of the braided conductor which are ensconced with the sealing composition. Thus, the step of alternating between an axial length of the braided conductor which is ensconced with sealing composition with an axial length which is substantially void of sealing composition solves the problem of having to remove the sealing composition from the braided conductor every time a length of cable is prepared for attachment to a transducer or sensor.
The next step is to extrude the inner jacket over the braided conductor immediately after the sealing composition is extruded over the braided conductor wherein the sealing composition is still in a substantially uncured state so that the sealing material will bond with the interior surface of the inner jacket. After the inner jacket has been extruded over the braided conductor the cable may be partially or fully cured. The central and penultimate strata form the coaxial assembly.
Once the coaxial assembly has been formed the essence of the above-process is repeated. Specifically, the exterior surface of the inner jacket is etched, by preferable running it through a chemical liquid etching bath, the braided sheath is then drawn or wound over the exterior surface of the inner jacket and is formed from a plurality of braided wire strands including interstices defined by spaces interposed between the wire strands forming the braided sheath.
Next, the cable is drawn through a die where a sealing material is extruded under pressure over and through the braided sheath and into contact with the inner jacket thereby completely filling in the interstices of the braided sheath substantially along its entire axial length and essentially making the braided sheath voidless. The sealing composition chemically bonds to the etched exterior surface of the inner jacket for forming a seal impervious to fluid wicking therebetween. As a final step the outer jacket is extruded over the triax braid thereby forming the triaxial assembly.
In an alternative embodiment of the instant invention, the communication cable is in a form of a coaxial cable. The coaxial cable includes a central strata, a penultimate strata and an ultimate strata concentrically disposed. The central strata includes a central signal transmission medium separated from the penultimate strata by a central insulator or dielectric. The penultimate strata includes a braided conductor circumscribing the dielectric. The ultimate strata includes an outer jacket circumscribing the braided conductor thereby forming the coaxial cable.
In the alternate embodiment, the communication cable is preferably manufactured in the form of the coaxial cable which is multiple meters in length. The manufacturing process may include the step of providing the central signal transmission medium or a central conductor which longitudinally extends from a first end to a second end and covering or extruding the dielectric over the central conductor. Next, the exterior surface of the dielectric is etched, by preferably running it through a chemical liquid etching bath.
The next step is to draw or wrap the braided conductor over the etched exterior surface of the dielectric wherein the braided conductor is formed from a plurality of braided wire strands including interstices defined by spaces interposed between the wire strands for forming the braided conductor. Next, the cable is drawn through a die where the sealing composition is extruded under pressure over and through the braided conductor and into contact with the etched dielectric thereby completely filling in the interstices of the braided conductor substantially along its entire axial length and essentially making the braided conductor voidless. The sealing composition chemically bonds to the etched exterior surface of the dielectric for forming a seal impervious to fluid wicking therebetween.
As a final step, the outer jacket is extruded over the braided conductor immediately after the sealing composition is extruded over the braided conductor wherein the sealing composition is still in a substantially uncured state so that the sealing composition will bond with the interior surface of the outer jacket. Alternatively, the sealing composition maybe partially or fully cured prior to the jacket being extruded over the braided conductor.
Accordingly, it is an object of the instant invention to provide a new and novel cable and method for precluding fluid wicking within an interior of the cable.
Another further object of the instant invention is to provide a cable as characterized above which is impregnated along an axial length of a braided conductor and substantially continuously impregnated along an axial length of a braided sheath circumscribing said braided conductor.
Another further object of the instant invention is to provide a cable as characterized above which substantially retains its original flexibility.
Another further object of the of the instant invention is to provide a cable as characterized above which retains its original ability to be electrically connected to a sensor.
Another further object of the instant invention is to provide a cable as characterized above which can be mass-produced as one continuously long length of cable which includes a braided conductor which is intermittently impregnated with a sealing composition along an axial length of the braided conductor and which when cut to an individual desired length includes a first axial length of the braided conductor which is ensconced with sealant and a second axial length adjacent the first axial length which is void of sealant such that the braided conductor retains its original electrical connectivity along the second axial length.
Viewed from a first vantage point, it is an object of the instant invention to provide a communication cable, comprising in combination, a first end and a second end, a conductor communicating the first end with the second end, a dielectric insulator circumscribing the conductor and including an exterior surface, a braided conductor circumscribing the insulator, the braided conductor formed from a plurality of braided strands having interstices therebetween, an axially extending zone of sealing composition impregnated into the braided conductor and filling the interstices along a first axial length of the braided conductor, interstices residing on at least one side of the axially extending zone being substantially void of sealant along a greater axial length then the first axial length of filled interstices.
Viewed from a second vantage point, it is an object of the instant invention to provide a communication cable, comprising in combination, a central strata, a penultimate strata circumscribing the central strata, an ultimate strata circumscribing the penultimate strata, a first zone of sealing composition impregnated within the penultimate strata and extending along a first axial length of the penultimate strata for abating fluid progression via fluid wicking within the penultimate strata, a second zone of sealing composition radially spaced from the first zone and impregnated within the ultimate strata for precluding fluid wicking within the ultimate strata, the second zone of sealing composition extending along a second axial length greater than the first axial length of the first zone of sealing composition.
Viewed from a third vantage point, it is an object of the instant invention to provide a process for making a communication cable for precluding fluid wicking, the steps including, utilizing a center conductor, circumscribing the center conductor with a dielectric, etching an exterior surface of the dielectric, circumscribing the dielectric with a braided conductor comprised of a plurality of braided strands having interstices therebetween, impregnating the braided conductor with a liquid sealing composition for forming an axially extending zone of sealing composition ensconcing and filling in an axial length of the interstices and radially extending to an area of tangency between the braided conductor and the etched exterior surface of the dielectric for bonding thereto, extruding an imperforate inner jacket over the braided conductor and the axially extending zone of sealing composition while both the axially extending zone of sealing composition and the inner jacket are both in a fluidic state for enhancing the bonding between an interior surface of the inner jacket and the radially and axially extending zone of sealing composition for filling in an axially extending area of tangency between the braided conductor and the axially imperforate inner jacket, curing the cable wherein the axially extending zone of sealing composition precludes fluid wicking along the braided conductor.
Viewed from a fourth vantage point, it is an object of the instant invention to provide a method for monitoring status of a shaft in a casing which requires a communication cable passing through the casing and preventing fluid from escaping from the casing through the cable by wicking and capillary attraction, the steps including, impregnating the cable with an uncured sealing composition, leaving the sealing composition off an interior axial length of the cable thereby providing at least one axially extending area void of sealing composition and at least one axially extending area impregnated with sealing composition, curing the sealing composition in the cable such that the cable abates fluid wicking and capillary attraction, connecting the axially extending area void of sealing composition to a transducer, positioning the transducer adjacent the shaft, and routing the cured, sealed cable through the casing to a data receiving unit.
Viewed from a fifth vantage point, it is an object of the instant invention to provide a method for monitoring status of a shaft in a casing which requires a communication cable passing through the casing and preventing fluid from escaping from the casing through the cable by wicking and capillary attraction, the steps including, forming the cable with sealing composition impervious to fluid and fluid vapor transmission, exposing cable conductors along an axial length of the cable, connecting the exposed end of the cable to a transducer, positioning the transducer adjacent the shaft, and routing the substantially uniformly cured cable through the casing to a data receiving unit wherein said sealing composition precludes fluid and fluid vapor from escaping from the casing.
Viewed from a sixth vantage point, it is an object of the instant invention to provide a communication cable, comprising in combination, a central strata and a penultimate strata concentrically disposed, a longitudinally non-continuous band of sealing composition interposed between the concentrically disposed strata for filling in interstices therebetween thereby abating fluid wicking propensity between the central strata and the penultimate strata.
Viewed from a sixth vantage point, it is an object of the instant invention to provide a communication cable, comprising in combination: a dielectric circumscribing a central conductor; a braided conductor circumscribing the dielectric; an imperforate jacket circumscribing the braided conductor; a longitudinally continuous band of sealing composition interposed between the dielectric and the imperforate jacket for filing in interstices therebetween wherein the sealing composition precludes fluid wicking along the braided conductor and leakage at areas of tangency between the braided conductor and both the dielectric and imperforate jacket.
These and other objects will be made manifest when considering the following detailed specification when taken in conjunction with the appended drawing figures.